The present invention relates to the art of removing tires from the rim in a tire/rim combination. More particularly, the present invention relates to improvements in the manner in which a tire bead is separated from the rim.
Over the last several years, Michelin has introduced a new style of tire/rim combination referred to as the Pax® system. Both the rim and tire of the Pax system are different from conventional tire/rim combinations. Moreover, the Pax system includes an internal support ring that functions to prevent unseating of the tire even with a sudden loss of pressure.
It is generally more difficult to remove a Pax system tire from the special rim than it is to remove a conventional tire from a standard rim. This is because conventional tubeless tire systems utilize a rim with a drop center to assure easy tire removal and replacement. The same physical feature is not present on a Pax system tire. With the Pax system, the tire's outer bead must be forced off of the rim first via levers and in a controlled manner. The internal support ring and inside bead are then removed via lateral force from an external roller.
It will thus be appreciated that removal of the first bead in the service or replacement of a Pax tire requires significant skill by the service person. In all cases the first procedure is to loosen the tire's bead from the rim and apply a thin liquid lubricant. This is typically accomplished by forcing a roller inboard against the tire bead creating a small gap between the tire bead and the rim. The service person then applies liquid lubricant into this opening around the entire bead diameter.
One of the earliest techniques for removal of a Pax system tire has involved the use of two levers to flip the bead up and over the edge of the rim. The tools are first inserted into the tire/rim intersection as the roller is pressing the tire from the rim. Next, the roller is moved away from the intersection and the two levers are maneuvered in a way to flip the bead from the rim. Considering that the Pax rim design has a small retainer lip on the outside edge, the lift levers could (and in many cases did) damage this surface. This brought on the use of protective clips made from plastic or metal. Often, however, the plastic only lasted a few times before deforming. Moreover, when using the protective clips, the operator was required to control two levers and two clips. This required a great deal of skill in a difficult situation.
A second approach for removal of a Pax system tire was to use a horseshoe device that had two bead lift profiles attached to one lever. This was also difficult to use and required skill to set in place for the bead lift process. This device also required protective rim clips.
A third known device is a single lever made from steel with a full jacket of plastic. The plastic is multipiece and screwed together. The plastic device allows protection and is allowed to slip in and out on the metal lift tool by a precise distance to assure rim protection and allow the tool to grasp the backside of the bead. However, on many attempts, the complete tool will be expelled by the tire's bead which requires the operator to reset the bead roller and reset the tool.